Compression sprayer



Sept 23, 1953 D. H. ANDERSON 2,853,212

COMPRESSION SPRAYER Filed Oct. 14, 1955 l .L l n United States Patent()CMPRESSION SPRAYER Donald H. Anderson, New Lenox, Ill., assignor to H.D.

Hudson Manufacturing Company, Chicago, Ill., a corporation of MinnesotaApplication ctober 14, 1955, Serial No. 540,390

19 Claims. (Cl. 222-402) The present invention relates to compressionsprayers of the type provided With a tank for receiving and containing aspray solution and a removable pump assembly mounted within the llingopening of the tank, and is directed more particularly to a novel meansand manner of detachably mounting and sealing the pump assembly in thetank, and to a novel check valve for controlling the ilow of air underpressure from the pump barrel on the downstroke of the pump plunger andsealing the barrel against the escape of air pressure from the tank intothe pump barrel on the upstroke of the plunger and during operation ofthe sprayer.

As compression sprayers operate under substantial air pressure that mustbe built up in the tank by the pump to permit such sprayers to theneffectively and continuously operate for a substantial period of time,much time and ettort has been expended and substantial expense incurredin the design and construction of compression sprayers in an attempt toprovide for- (l) Quick and easy insertion and retention of the pumpassembly in the tank;

(2) Positive sealing of the pump assembly in the tank;

(3) Quick release and removal of the pump assembly for replenishing thetank with a liquid or spray solution when the supply therein has beenexhausted;

(4) Means whereby to release the contained pressure in the tank prior toremoval of the pump assembly and thereby prevent forcible ejection ofthe pump assembly from the tank by the entrapped pressure which maycause injury to the operator.

The present invention has for an object to provide a simple and mosteffective means and manner for inserting, mounting and retaining thepump assembly in the tank, positively sealing said assembly in the tankwithout the use of cams, levers, screw threads or the like, releasingthe tank pressure to permit the subsequent removal of the pump assemblywithout danger of pressure induced forcible ejection of the assembly andnally enabling the speedy and easy release and removal of the assemblyfrom the tank.

A further object of the present invention is to provide a novel pumpunit or assembly having a pump cylinder and plunger capable ofgenerating a requisite air pressure in the tank for continuous spraying,said cylinder having a protruded annular enlargement near the upper endthereof. An expansible elastic sleeve surrounding the upper end of thecylinder and adapted to be positioned over the protruded enlargementforms a most effective sealing contact between the cylinder protrusionand the neck of the filling opening in the tank. Such sealing contact ismaintained and becomes more elective as pressure builds up in the tank.

The novel sealing arrangement also provides a quick release forrelieving the pressure in the tank after which the pump assembly may beremoved for access to the filling opening to replenish the supply ofspray solution or liquid in the tank.

Another important object of the present invention is to Patented Sept.23, 1958 provide a novel and simple form of check valve for controllingthe flow of air under pressure from the barrel during pumping operationand for sealing the barrel against the escape therethrough of pressurein the tank during each upstroke of the pump plunger and during thespraylng operation.

A further object of the present invention is the provision in acompression sprayer of a pump unit including a cylinder having aprotrusion adjacent each end thereof, the upper protrusion cooperatingas previously stated with an expansible surrounding sleeve to provide anovel mounting and a seal between the cylinder and the neck of the tank,and also provide for the entrance of air into the cylinder beneath theplunger at the top of each piston stroke. The lower protrusion of thecylinder also has a dual function in that it prevents upwarddisplacement of the elastic band or check valve mounted on the lower endof the cylinder, and also provides space for the expansion of thedepending flange of the cup packing beyond the normal internal diameterof the cylinder at the end of each down or compression stroke.

Further objects are to provide a construction of maximum simplicity,eiiciency, economy and ease of assembly and operation, and such furtherobjects, advantages and capabilities as will later more fully appear andare inherently possessed thereby.

In the drawing:

Figure 1 is a view in vertical cross section through a compressionsprayer and pump assembly embodying the present invention, the pumpassembly being in position to be lowered into operative position in thetank or container.

Fig. 2 is a view similar lto Fig. l, but with the pump assembly in itslowered operative position in which the pump is anchored in sealingengagement in the neck of the tank.

Fig. 3 is a top plan view of the assembled compression sprayer with thehandle moved or rotated to carrying position. v

Fig. 4 is a fragmentary enlarged view in vertical cross section throughthe upper end of the pump cylinder show- Iing the lower end of theplunger.

Fig. 5 is a fragmentary enlarged view in vertical cross section throughthe lower end of the pump cylinder provided with my novel check valve,the pump plunger being near the lower end of its downstroke.

Referring more particularly to the disclosure in the drawing and to thenovel illustrative embodiment therein shown, the novel compressionsprayer assembly comprises a tank or container 10 adapted to receive andcontain a quantity of liquid or spray solution supplied thereto throughthe opening 11 from the upwardly ared pour- ICC -ing funnel 12 of thetank. Fig. l shows the pump unit 13 in position to be lowered andassembled in the tank in the operative position of Fig. 2.

The pump unit or assembly 13 comprises a pump cylinder or barrel 14 inwhich is slidably mounted a plunger including a piston rod .15projecting through and guided bya cap or closure 16 at the upper end ofthe cylinder and a piston including a cup packing 17 having a dependingand outwardly ared annular llange 18, anchored between an upper plate 19and a lower inverted cup member 21.

To lock or retain the piston parts on the lower end 24 of the piston rod15, the latter is threaded and the packing 17, the plate 19 and theinverted cup member 21 are provided with aligned openings to receive thethreaded lower end 24 of the rod 15 on which these parts are secured byspaced lock nuts 25.

The member 21 includes a depending annular ange 22 adapted to abut inits lowermost position an end plate or closure 23 forming the lower endof the pump Cylinder 14, by which the downward movement of the plungerin the cylinder is limited. The depending ilange 22 is of such length asto prevent the depending liange 18 of the packing 17 from contacting theend plate 23.

The pump cylinder is expanded to form an annular enlargement orprotrusion 26 adjacent its upper end, and also an enlargement 27adjacent its lower end, for a purpose which will be later explained.Detachably mounted on the upper end of the cylinder 14 is the cap orplunger rod guide 16 which functions (l) to guide the rod 15 in thecenter of the cylinder 14, (2) to provide a closure for the upper openend of the cylinder to prevent the entrance'of foreign matter, and (3)carries an elastic expansible collar or sleeve 28 preferably formed ofnatural or compounded synthetic rubber and longitudinally movable on thecylinder 14. This eapansible collar 28 is adapted to surround andembrace the upper end of the pump cylinder and the upper end of thecollar is aixed or anchored to the cap or closure 16 by being clampedbetween an insert or disc 29 and an external depending flange 31 on thecap or closure 16.

The closure 16 and the insert 29 have aligned, centrally arrangedopenings through which loosely projects the piston rod 15 so as to befreely reciprocable in the closure 16 to draw air into the cylinder uponmanipulation of a handle 32 aflixed to the upper end of the rod 15.

When the plunger is elevated to its uppermost position, the cup packing17 of the piston is in substantially the position shown in Fig. 4wherein the packing no longer contacts the interior wall 33 of the pumpcylinder 14 but enters the upper protrusion or enlargement 26 of thecylinder where the flange 18 of the packing 17 is spaced from thesurrounding walls. Thus air is permitted to enter the cylinder bypassing around the packing as indicated by the arrows in Fig. 4,whereupon as the plunger is pressed downwardly this air is forced fromthe cylinder into the surrounding space of the container.

To enable a pressure to be built up in the tank by reciprocation of thepump plunger and retained therein for discharging the spray solutionthrough the tube 34 to a spray nozzle (not shown), I have devised anovel check valve to prevent back-How of pressure from the tank to thepump. This valve comprises a band 3S of an elastic, liexible material,such as natural or compounded synthetic rubber surrounding the lower end36 of the cylinder 14 which is slotted or provided with openings aboutits circumference providing ports 37 for the discharge of air underpressure.

The elastic and compressible band 35 is held in operative position bythe protrusion 27 above and the external ange 30 below on the closure23. The band is contracted by slight tension and by the air pressure inthe tank pressing it against the exterior of the cylinder 14 so that onthe upstroke of the plunger, this valve member or band 35 effectivelycovers and seals the ports against reverse fluid flow from the tank intothe pump cylinder. On the downstroke of the plunger, air under pressureis forced outwardly from the cylinder through the ports 37 and into thetank by stretching and temporarily expanding this valve memberconsisting of the band 35. This Y valve consisting merely of a exibleband may be readily assembled on the cylinder and removed for cleaningor replacement. The cost of this valve is but a small fraction of thecost of prior types of mechanical valves ernployed in compressionsprayers.

To mount or assemble the present novel pump unit 13 in the tank 10 andto effectively seal it for operation after each filling of the tank forwhich the pump unit or assembly must be removed for access to thefilling opening of the tank, the pump cylinder 14 is provided at itsupper end with the flexible collar or sleeve 28 and at its lower endwith a coil spring 38 suitably axed at one end to the end plate orclosure 23 of the pump cylinder. Upon insertion of the pump unit orassembly 13 to the position shown in Fig. l with the collar 28encompassing the upper end of the cylinder 14, the handle 32 is turnedto the position shown where the curved upper end 39 of a pair of hookmembers 41 is adapted to engage or be received in aligned grooves orrecesses 42 in the base or underside of the handle 32. In this position,pressure may be applied to the handle and simultaneously to the hookswhich are adjustably secured to the insert or disc 29 of the closure 16,whereby the collar or sleeve 28, being a close fit around pump cylinder14, presses downwardly against the protrusion 26' thereby forcing thecylinder assembly downwardly in the tank 10 until the spring 38 iscompletely compressed or the resistance offered therebyis greater thanthe frictional resistance of the collar 28 to sliding movement on thecylinder 14. At such time the protrusion 26 of cylinder 14 is withintank 10, below the opening 11. Continued downward pressure on handle 32opposed by the now immobile cylinder 14 forces the collar 28 to expandand slide downward over protrusion 26, thus increasing the outerdiameter of the annular enlargement so that it cannot be withdrawnthrough opening 11.

Upon release of downward pressure applied to the handle 32 and to thecap or cover 16, the expansible coil spring 38 will force the pump unitor assembly 13 upwardly and with the air pressure within the tank 10effectively seal the pump barrel or cylinder 14 in the neck of the inletor filling opening 11, with the elastic collar 28 wedged between theenlargement on the cylinder and the throat 43 of the tank. With thecollar 28 in the sealing and operative position of Fig. 2, the pump isprevented from being removed from the tank except as hereinafterdisclosed. To now operate the assembled pump unit to build up airpressure in the tank, the handle 32 is rotated until it is disposedbetween the hook members 41, whereupon the handle may be manipulated toreciprocate the plunger.

If the compression sprayer is to be carried about, the handle 32 isrotated or moved to the position of Fig. 3 in which the base of thehandle is engaged beneath the hook members 41 so that the tank andcontents may be lifted and carried about by the handle.

To release the tank pressure prior to refilling the tank, the handle 32is rotated or moved to the operative position shown in Fig. 2 whereinthis handle is located between the spaced hook members 41. With bothhands the operator then presses down on the handle 32 until the spring38 is compressed sufiiciently to break the seal between the throat 43-of the tank 10 and the collar 2S, whereupon the air pressure in thetank is relieved through the passage between the cylinder 14 and thesurrounding` walls of throat 43.

To remove the pump from the tank the operator continues to press down onthe handle with one hand and at the same time grasps with a linger ofeach hand one of the hook members 41 and pulls upwardly on these hookmembers until the elastic or resilient collar or sleeve 28 is withdrawnover the enlargement 26. Then with the resilient coll-ar or 'sleeve 28in its elevated position on the pump barrel or lcylinder 14, downwardpressure on the handle 32 may be relieved, thereby permitting the spring38 to raise the released pump unit 13 in the inlet or filling opening ofthe tank to approximately the position shown in Fig. l. Thereafter, theentire pump assembly 13 may `be manually lifted out of the fillingopening 1l of the tank 10.

By providing the pump cylinder 14 with protrusion 26 of somewhat smallerdiameter than the lilling opening 1l and Iwith the novel resilientcollar 23 carried by the cap or cover 16 and adjustable on the cylinder,a most effective sealing means is provided. Furthermore, this protrusion26 provides a novel valve arrangement permitting free air to enter thecylinder 14 at the top of each upstroke of the plunger (Fig. 4). This isa highly important advantage over an 'air pump provided with acontinuous cylindrical barrel wherein `as the plunger is drawn upward apartial vacuum must be created in the cylinder in order that air atatmospheric pressure may enterv around the plunger leather and into thecylinder below the plunger. With the present pump unit when the plungeris elevated to the position shown in Fig. 4, air at atmospheric pressurecan freely enter the cylinder 14 about the cup packing, thus assuringthe pump a full cylinder of air at atmospheric pressure `at thebeginning ofeach stroke.

The hook members 41 are preferably threaded into the cap or cover 16 andthe insert or disc 29 for longitudinal adjustment whereby their 'heightmay be varied. Lock nuts 44 lock these hook members in their adjustedposition.

With the simple form of valve member disclosed in Fig. 5, no specialvalve seat or retaining means for the valve is required. There is but asingle moving part, i. e., the `elastic or resilient band 3 whichlencircles the lower end 36 of the pump barrel 14 under slight tensionand forms an eifective seal on the upst-roke of the pump plunger bycovering and sealing the ports 37 by its own elasticity and contractionand by the pressure in the tank. On the downstroke, this band permitsthe outilow of air through the ports 37 by stretching as the air underpressure is forced through these ports.

The lower enlargement Z7 of the pump cylinder has a two-fold function inthat it retains the check valve member or elastic band 3S in positionbetween it and the external iiange on the end cap or closure 23, andpermits the annular ange 18 of the cup packing 17 to expand into thisenlargement `whereby the leather or composition of the packing ismaintained supple and its life prolonged. As clearly shown in Fig. 2,this flange 1S of the packing 17 is held out of contact with the base orend plate 23 of the barrel 14 by the depending iiange 22 of the invertedcup member 21 formed of metal or `other rigid material suitable for thepurpose.

From the above description and the disclosure in the drawing, it will beapparent that the pre-sent invention comprehends a novel pump assembly,a novel means and manner of sealing this pump assembly in the tank whichassures optimum safety as the pump ycannot be withdrawn for illing thetank until al1 pressure is relieved in the tank, and a novel, simplifiedand highly eifective check valve for the pump.

Having thus disclosed the invention, I claim:

1. A compression sprayer` comprising a tank having a filling opening, acompression pump including a cylinder proportioned to Abe insertedthrough said opening into said tank, a `sealing sleeve surrounding theupper portion of said cylinder and also proportioned to be insertedthrough said opening, and means on said cylinder for enlarging saidsleeve beyond the dimension of said opening whereby the opening may beclosed to seal the tank.

2. A compression sprayer comprising a tank having a iilling opening, apump cylinder having a closed lower end, a circumferential enlargementnear each end and eX- haust ports in proximity to the lower enlargement,an elastic band surrounding the ported portion of said cyl-V inderbiased to close said ports, a sleeve surrounding Vthe upper portion ofsaid cylinder, and means whereby said sleeve may be adjustedlongitudinally of said cylinder to cooperate with the upper cylinderenlargement in sealing said tank opening.

3. In a compression sprayer, a tank provided with a neck defining afilling opening, a pump unit removably mounted in the iilling openingand including a cylinder, and means for detachably mounting land sealingthe cylinder in the neck of the tank, said means comprising a protrusionon the cylinder adjacent its upper end and an elastic collar slidablymounted on the upper end of the cylinder with its lower end adapted tobe forced over the protrusion when the cylinder is lowered in the tankand the protrusion is disposed below the neck of the iilling openingwhereupon the elastic collar is wedged between the protrusion and theneck of the tank when the cylinder is moved to operative position.

4. In a compression sprayer, a tank provided with a constrictiondefining a illing opening, a pump unit removably mounted in the fillingopening and provided with a barrel, and means for detachably mountingand sealing the barrel in the constriction of the tank, said meanscomprising an enlargement on the barrel adjacent its upper end and ofless external diameter than the constriction, an elastic collarslida'bly mounted on the upper Iend of the barrel `with its lower endadapted to be forced over the enlargement when the barrel is lowered inthe tank and the enlargement is disposed below the neck of the fillingopening whereupon the elastic collar is wedged between the protrusionand the neck of the tank when the barrel is elevated, and means forspring-biasing the barrel to elevated position.

5. In a compression sprayer, a tank provided with a neck deining afilling opening, a pump unit removably mounted in the lling opening andprovided with a barrel, and means for detachably mounting and sealingthe barrel in the neck of the tank, said means comprising a protrusionon the barrel adjacent its upper end having an external diameter`somewhat less than the internal diameter of the neck of the tank, aresilient sleeve adjustably mounted on the upper end of the barrel withits lower end adapted to be forced over the protrusion when the barrelis lowered in the tank and the protrusion is disposed below the neck ofthe filling opening, and a coil spring disposed below the lower end ofthe barrel and the bottom of the tank for spring-biasing the barrel toelevated position to wedge the resilient sleeve between the protrusionand the neck of the tank for sealing the interior of the tank.

6. In a compression sprayer, a tank provided with a constrictiondefining a filling opening, a pump unit removably mounted in the fillingopening and provided with a cylinder having an enlargement adjacent tobut spaced from the upper end of the cylinder with said enlargementconformably received within the constriction, and means for removablymounting the pump unit in the iilling open ing and providing sealingengagement between said enlargement and the constriction of the tank,said means inc-luding a resilient sealing `collar longitudinallyadjustable on the outer end of the cylinder whereby when the cylinder islowered into the tank with the enlargement disposed below theconstriction of the tank and the resilient collar is forced downwardlyover the upper end of the `cylinder with the lower end of the collarover the enlargement, the resilient collar is wedged between theenlargement on the cylinder and the neck of the tank when theenlargement is located immediately below the neck.

7. In a compression sprayer, a tank provided with a constrictiondefining a filling opening, a pump unit removably mounted in the fillingopening and provided with a cylinder having `an open outer end and aprotrusion adjacent to but spaced from its outer end with saidprotrusion capable of being received within the constriction, and meansfor removably mounting and sealing the pump unit in the filling openingwith the inner end of the cylinder projecting into the tank, said meansincluding a cover for the outer end of the cylinder, a resilient sealingcollar carried by the cover and encompassing the outer end of thecylinder and longitudinally adjustable thereon whereby when the cylinderis projected into the tank with the protrusion located within the tankand adjacent the constriction and the cover is depressed to force theresilient collar longitudinally over the outer end of the cylinder andover the protrusion, said collar upon retroactive movement of thecylinder becomes wedged between the protrusion and the constriction ofthe. tank, and means for spring-biasing the cylinder to maintain thecollar in sealing engagement between the protrusion on the cylinder andthe constriction of the tank.

8. In a compression sprayer, a tank having a constriction providing alling opening for the tank, a pump unit adapted to be mounted in theconstriction and comprising a pump .cylinder having a protrusionadjacent the upper end of the cylinder, said cylinder being open at itsupper end and provided with a closure at its lower end, a compressionspring disposed between the closure and the bottom of the tank forspring-biasing the pump unit to elevated position, a cover for the upperopen end of the cylinder and provided with a depending sleeve of elasticmaterial encompassing and gripping the upper end of the cylinder butmovable relative thereto whereby the cover and its sleeve are movablelongitudinally of the upper end of the cylinder, said sleeve when thecylinder is lowered into the tank and the cover and cylinder aredepressed against the compression spring to locate the protrusion on thecylinder below the constriction in the tank and the lower end of theelastic sleeve is slid downwardly over the protrusion, release ofdownward pressure on the cover and cylinder of the pump unit causes thecompression spring to elevate the cylinder and wedge the elastic sleevebetween the protrusion and the constriction whereby t anchor thecylinder of the pump unit in sealing engagement with the constriction inthe tank.

9. In a compression sprayer, a tank having a constriction providing ailling opening, a removable pump unit including a pump cylinder adaptedto be readily inserted into and removed from the constriction in thetank, a

pump plunger mounted in the cylinder and provided withY a handle forreciprocating the plunger to supply air under pressure to the tank, saidcylinder having a protruded portion adjacent the upper end of thecylinder and an elastic sealing member slidably mounted on the upper endof the cylinder adjacent said protrusion and providing sealingengagement between the protrusion on the cylinder and the constrictionof the tank when wedged therebetween, said sealing engagement beingreleased when the pump handle is pressed downwardly to depress thecylinder whereby to relieve the pressure in the tank, after which thepump unit may be withdrawn.

l0. In a compression sprayer, a tank having a constriction providing afilling opening, a removable pump unit including a pump cylinder adaptedto be readily inserted into and removed from the constriction in thetank and provided with a protrusion adjacent its upper end, a pumpplunger mounted in the cylinder and provided with a plunger rod and ahandle for reciprocating the plunger to supply air under pressure to thetank, a cap for the upper open end of the cylinder and providing a guidefor the plunger rod and a cover for the top of the cylinder, a dependingcollar of an elastic material carried by said cap and encompassing andgripping the upper open end of the cylinder but longitudinally movablethereon and over the protrusion, a closure for the lower end of thecylinder, a compression spring between the closure and the bottom of thetank for spring-biasing the cylinder and pump unit to elevated position,hook members rigidly secured to and carried by the cover for thecylinder adjacent the plunger handle, said hook members being adapted tobe depressed by the pressure applied to the handle when the pump unit isto be inserted into the tank, whereby the handle depresses the collaruntil the cylinder compresses the spring, said handle thereafterdepressing the hook members to slide the elastic collar over theprotrusion at the upper end of the cylinder, whereupon release ofpressure applied to the handle permits the compression spring to elevatethe cylinder and wedge the depending collar between the protrusion andthe constriction of the tank, said sealing engagement being releasedwhen the pump handle is pressed downwardly with sufcient pressure todepress the cylinder and compress the spring whereby to break thesealing engagement and relieve the pressure in the tank, after which thepump unit may be withdrawn. A

l1. In a compressing sprayer, a tank having a lconstricted neck forreceiving the spray solution to be dispensed, a pump unit for supplyingair pressure to the tank and including a pump cylinder removably mountedin the constritced neck, a cap for said cylinder, a plunger for saidcylinder having a rod mounted for reciprocation in the cap and cylinderand a handle for manipulating the rod and plunger, and means fordetachably mounting and sealing the cylinder and pump unit in operativeposition in the constricted neck of the tank but permitting removal ofthe pump unit for replenishing the contents of the tank, said meansincluding a protrusion `on the cylinder adjacent its upper end with saidprotrusion having an external diameter less than the internal diameterof the constricted neck to permit the cylinder to be lowered in the tankwith the protrusion disposed below the constricted neck of the tank whenthe pump unit is mounted in operative position, and a resilient c-ollarcarried by the cap and encompassing the upper end of the cylinder andadjustable oil the cylinder to slide over the protrusion and providesealing engagement between the protrusion on the cylinder and the-constricted neck of the tank.

12. In a compression sprayer, a tank provided with a neck defining aiilling opening, a pump unit removably mounted in the filling openingand provided with a barrel, a plunger including a rod mounted forreciprocation in the barrel and a packing carried at the lower end ofthe rod and conformably received and longitudinally movable in thebarrel for supplying air under pressure to the tank as said rod isreciprocated, said `barrel having a protrusion adjacent its upper endand an elastic collar slidably mounted on the upper end of the barrelwith its lower end adapted to be forced over the protrusion when thebarrel is lowered in the tank and the protrusion is disposed below theneck of the lling opening whereupon the elastic collar is wedged`between the protrusion and the neck lof the tank to provide a sealthereat when the barrel is moved to operative position, the internaldiameter of said protrusion being greater than the external diameter ofthe packing to provide an annular space between the packing and theprotrusion for the entrance of air under atmospheric pressure into thebarrel at the top of the stroke of the plunger.

13. In a compression sprayer, a tank provided with a neck defining atilling opening, a pump unit removably mounted in the tilling openingand provided with a barrel, a plunger including a rod and a packingcarried at the lower end of the rod and conformably received andlongitudinally movable in the barrel for supplying air under pressure tothe tank as said rod is reciprocated, said barrel having an enlargementadjacent its upper end for receiving the packing at the top of thestroke of the plunger, said enlargement being of greater diameter thanthe packing to provide an annular space about the pack- Aing for theentrance ofvair under atmospheric pressure into the barrel at the topIof the stroke of the plunger.

14, In a compression sprayer, a tank having a constriction providing afilling opening, an air pump mounted in the filling opening and providedwith a cylinder depending into the tank and a pump plunger for supplyingair under pressure to the tank, said cylinder having a protrusionadjacent its upper end and another protrusion adjacent its lower end, anelastic sealing collar encompassing the upper end of the cylinder andwhen the air pump has -been assembled in the constriction of the tanksaid sealing collar forms a tight sealing contact lbetween the upperprotrusion on the cylinder and the encompassing constriction of the tankfor anchoring the pump in the tank, said upper protrusion furtherproviding the interior of thel cylinder with a passage for the entranceof air under atmospheric pressure into the cylinder about the pumpplunger when the plunger reaches the top of its upstroke, the lower endof the cylinder below the lower protrusion having multiple openingsproviding discharge ports for the passage of air under pressure from theinand a check valve comprising an elastic band encompassing the cylinderabout the discharge ports for controlling rllow through said ports, saidlower protrusion providing space for the expansion of the pump plungerat the limit of its downstroke and retaining the elastic band on thecylinder.

15. In a compression sprayer, a tank provided with a neck dening alilling opening, a pump unit removably mounted in the filling openingand provided with a cylinder, a plunger longitudinally movable in thecylinder for supplying air into the tank to build up pressure in in thetank, said cylinder having a closure at its lower end and an enlargementabove said closure, discharge ports provided in the circumference of thecylinder adjacent its lower end between said enlargement and saidclosure for the passage of air from the cylinder into the tank on thedownstroke, and a resilient band encompassing said cylinder and disposedabout the discharge ports to prevent air in the tank from returning intosaid cylinder on the upstroke, said enlargement providing for expansionof the pump plunger at the limit of its downstroke.

16. In a compression sprayer, a tank having a constriction providing alling opening, an air pump mounted in the lling opening and providedwith a cylinder depending into the tank and a pump plunger for supplyingair under pressure to the tank, said cylinder having a protrusionadjacent its lower end and a closure at the bottom of the cylinderprovided with an external flange, the lower end of the cylinder belowthe protrusion having multiple openings providing discharge ports forthe passage of air from the interior of the cylinder into the tank oneach downstroke of the plunger, and a check valve comprising acompressible band encompassing the cylinder about the discharge portsfor preventing the return of air from the tank into the cylinder, saidprotrusion providing space for the expansion of the pump plunger at thelimit of its'downstroke and said band being retained tbetween saidprotrusion and the ange on said closure.

17. In a compression sprayer, a tank, a pump unit mounted in the tankand including a pump barrel depending into the tank, a pump plunger insaid barrel for supplying air into the tank under pressure, said barrelhaving a closure at its lower end and enlargement above said closure,discharge ports in the barrel between said enlargement and said closurefor the passage of air from the barrel to the interior of the tank underpressure, and a compressible band providing a check valve for saidports, said band encircling the barrel about said ports and maintainedon the barrel whereby on the upstroke of the pump plunger said bandcovers the ports and the air pressure in the tank presses the bandagainst the barrel thus forming the check valve to prevent the return ofair into the barrel, and on the downstroke of the pump plunger the airunder pressure in the barrel stretches the band sulciently to dischargethe air through the ports into the tank, said enlargement providingspace for the expansion of the pump plunger at the limit of its downwardstroke.

18. A compression sprayer comprising a tank provided with an opening, apump having a plunger provided with an operating handle and a cylinderextending through said opening and longitudinally movable therein, saidcylinder having an annular enlargement adjacent its upper end movablethrough said opening, a spring at the lower end of said cylinder, and anexpansible sleeve surrounding and longitudinally slidable on saidcylinder and over said enlargement when said cylinder is inserted andlowered into said tank by downward pressure on said pump handle, and inthis inserted and lowered position with the enlargement and the portionof the sleeve about said enlargement disposed within the tank, whendownward pressure on said pump handle is released, the spring which iscompressed between the lower end of pump cylinder and the bottom of tankelevates the cylinder and eiects sealing by pressing the sleeve aboutsaid enlargement upwardly against the tank opening, whereupon airpressure produced within the tank by operation of the pump increases theupward thrust of the cylinder against the tank opening, thus tighteningthe seal.

19. A compression sprayer comprising a tank provided with a 'illingopening, a compression pump cylinder insertable through said opening andmeans including a protrusion on said cylinder and a longitudinallyslidable elastic sleeve surrounding the upper portion of said cylinder,said sleeve being extensible over said protrusion when the cylinder islowered in the tank until the protrusion and surrounding portion of thesleeve is within the tank below the lilling opening, and means forelevating said cylinder whereby the portion of the elastic sleeve oversaid protrusion closes said opening and with the air pressure within thetank maintains sealing engagement.

References Cited in the tile of this patent UNITED STATES PATENTS410,848 McHugh Sept. l0, 1889 1,971,727 Parrott Aug. 28, 1934 2,715,980Frick Aug. 23, 1955 UNITED STATES PATENT oTTTCE CERTIFCATE @E CRECTINPatent Nm 2,853,232 September 239 1958 n Donald Ha Anderson It is herebyCertified that error appears n the printed specification of the abovenumbered patent requiring correction and that the said Letters Patentshould read as corrected belowe Column 6, lines 69 and. '73, for"retroaotve" read retraotve n;

oolulrn 89 line 3, for "oonstritoed" u cone-triste f :ma

Signed and sealed this 6th day of January 1959.,

Attest:

KARL H, AXLTNE Attesting Officer ROBERT C. WATSON Commissioner ofPatents

